/*
 * Copyright 2009-2013 Aarhus University
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package dk.brics.tajs.util;

/**
 * Pair of objects.
 */
public class Pair<F,S> {

	private F first;
	
	private S second;
	
	private Pair(F fst, S snd) {
		this.first = fst;
		this.second = snd;
	}

	/**
	 * Constructs a new pair.
	 */
	public static <F,S> Pair<F, S> make(F fst, S snd) {
		return new Pair<>(fst,snd);
	}

	@Override
	public int hashCode() {
		final int prime = 31;
		int result = 1;
		result = prime * result + ((first == null) ? 0 : first.hashCode());
		result = prime * result + ((second == null) ? 0 : second.hashCode());
		return result;
	}

	@Override
	public boolean equals(Object obj) {
		if (this == obj)
			return true;
		if (obj == null)
			return false;
		if (getClass() != obj.getClass())
			return false;
		Pair<?,?> other = (Pair<?,?>) obj;
		if (first == null) {
			if (other.first != null)
				return false;
		} else if (!first.equals(other.first))
			return false;
		if (second == null) {
			if (other.second != null)
				return false;
		} else if (!second.equals(other.second))
			return false;
		return true;
	}

	/**
	 * Returns the first object.
	 */
	public F getFirst() {
		return first;
	}

	/**
	 * Returns the second object.
	 */
	public S getSecond() {
		return second;
	}
	
	@Override
	public String toString() {
		return "(" + first + ", " + second + ")";
	}
}
